In the field of electronic materials, the recent advances of the degree of integration, multi-functionality and performance-improvement of semiconductor devices have resulted in the considerable increases of the circuitry resistance and the condenser capacity observed between distributing wires of the devices and this in turn leads to increases of the electric power consumption and the delay time. In particular, the increase of the delay time may be a principal cause for the reduction of the signal-processing or -transmitting speed of devices and the generation of crosstalk among others, and accordingly, it has been desired for the elimination or reduction of any parasitic resistance and any parasitic capacity in order to reduce the delay time and to thus make the operational speed of a semiconductor device higher. As one of specific means for reducing the parasitic capacity, it has been tried to cover or coat the periphery of the distributing wires with a low dielectric interlayer insulating film.
In addition, the interlayer insulating film should have excellent heat resistance so that the insulating film can withstand the post-processes carried out under severe conditions and encountered when producing a substrate for packaging, such as a thin film-forming step, a tip-connecting step and a pin-attaching or -arranging step; as well as high resistance to chemicals so as to withstand any wet process. Further, there have recently been adopted Cu distributing wires having a low resistance in place of the Al distributing wires currently used. Correspondingly, the CMP (Chemical Mechanical Polishing) technique has in general been selected for the planarization of the distributing wires and insulating films and therefore, the interlayer insulating film should have a high mechanical strength sufficient for the film to withstand this process.
As organic polymeric interlayer insulating films, there have long been known or disclosed, for instance, polybenzoxazoles, polyimides and polyarylenes (ethers), but it has been desired for the development of a material having a lower dielectric constant in order to realize a higher-speed device. However, these materials should further be improved since they suffer from various problems. For instance, if heteroatoms such as oxygen, nitrogen and/or sulfur atoms or aromatic hydrocarbon units are introduced into a polymer molecule like the foregoing materials, the dielectric constant of the polymer increases due to the high molar polarization, it is likewise increased with time because of the moisture absorption of the polymer and the reliability of the resulting electronic devices would in turn be reduced considerably.
On the other hand, the polymers each constituted by saturated hydrocarbons have a low molar polarization as compared with the polymers each constituted by heteroatom-containing units and/or units derived from aromatic hydrocarbons and therefore, the former polymers have such a merit that they show lower dielectric constants. However, the hydrocarbons having high degrees of flexibility such as polyethylenes are insufficient in the heat resistance and accordingly, they cannot be used in the applications as electronic devices.
In this respect, there have been disclosed polymers each comprising, in the molecule, a rigid saturated hydrocarbon having a cage-like structure such as adamantane or di-adamantane and it has also been disclosed that the insulating film derived from such a polymer shows high heat resistance and a low dielectric constant (Japanese Un-Examined Patent Publication 2004-504455). However, it has been known that these films are insufficient in the storage stability with the elapse of time. They accordingly suffer from a problem to be solved such as the increase of the dielectric constant with time.
On the other hand, there has been proposed a low dielectric material having a di-yne structure (Japanese Un-Examined Patent Publication 2002-155233). This is a material for forming an insulating film which is excellent in the mechanical strength, heat resistance and durability, but the initial value of the dielectric constant thereof is rather high on the order of 2.7-2.9 and accordingly, it has been desired for the further reduction of the dielectric constant thereof. Moreover, the film formed from this material suffers from such a problem that the dielectric constant thereof would increase with time and therefore, the material should further be improved in this respect.